1. Field of the Invention
The present invention relates to an electrode-built-in susceptor and a manufacturing method therefore. In particular, the present invention relates to an electrode-built-in susceptor having a superior durability under a high temperature oxidizing atmosphere. Also, the present invention relates to method for a manufacturing an electrode-built-in susceptor with a high product yield in a low product cost.
2. Description of Related Art
In recent years, manufacturing processes such as an etching process, a coating process are performed per a wafer or per a base board uniformly in a production process for a semiconductor device such as an IC (integrated circuit), an LSI (large scale integration), VLSI (very large scale integration). It is the same for manufacturing process for a display device such as a liquid crystal display (LCD) and a plasma display (PDP) and an assembly process for a hybrid IC of the like. A sheet-by-sheet process for a plate sample such as a semiconductor device, a glass base board for a liquid crystal, and a printed circuit board is becoming more common.
In such a sheet-by-sheet process, a plate sample is supported in a processing chamber sheet by sheet, or wafer by wafer. The plate sample is mounted on a sample base which is called as a susceptor and processed for a predetermined time.
It is necessary that such a susceptor can be used under a high temperature plasma condition. Therefore, it is required that such a susceptor has a superior plasma characteristics and a larger thermal conductivity.
For such a susceptor, a susceptor which is made of a aluminium-nitride-group-sintered-member having superior high temperature anti-plasma characteristics is commonly used.
There is a case in which an electrostatic chucking electrode for fixing a plate sample by generating an electric charge and an electrostatic absorbing force is disposed in the susceptor. Also, there is a case in which a heating electrode for heating the plate sample by an electricity is disposed in the susceptor. Also, there is a case in which an inner electrode for generating a plasma by applying a high frequency electricity is disposed in the susceptor.
FIG. 5 is a cross section showing an example for an electrode-built-in susceptor in which such an inner electrode is built thereinside. An electrode-built-in susceptor (1) comprises a mounting plate 2 which is made of an aluminium-nitride-group-sintered-member of which upper surface is a mounting surface 2a on which a plate sample is mounted, a supporting plate 3 which is made of an aluminium-nitride-group-sintered-member which is attached to the mounting plate 2 unitarily, an inner electrode 4 which is disposed between the mounting plate 2 and the supporting plate 3, and power supplying terminals 6, 6 which are disposed in a fixing hole 5 in the supporting plate 3 such that the power supplying terminals 6, 6 contact the inner electrode 4.
The power supplying terminal 6 is made of a conductive aluminium-nitride-tungsten-composite-sintered-member.
Such an electrode-built-in susceptor 1 having such a structure is produced as follows. First, fixing holes 5, 5 which penetrate a supporting plate 3 which is made of a aluminium-nitride-group-sintered-member are formed in a thickness direction of the supporting plate 3. The power supplying terminals 6, 6 which are made of a conductive aluminium-nitride-tungsten-composite-sintered-member are fixed in the fixing holes 5, 5. Next, a member 7 which contains a conductive powder is applied and dried on the supporting plate 3 such that the member 7 contacts the power supplying terminals 6, 6. Consequently, the supporting plate 3 and the mounting plate 2 which is made of an aluminium-nitride-group-sintered-member are attached together via a surface of the member 7 which is applied on the supporting plate 3. Furthermore, the supporting plate 3 and the mounting plate 2 are heated under a compressed condition unitarily. Thus, the member 7 is sintered and an inner electrode 4 is formed between the supporting plate 3 and the mounting plate 2.
In the electrode-built-in susceptor 1, the power supplying terminal 6 is attached to the inner electrode 4 together reliably; therefore, a conductivity in the electrode-built-in susceptor 1 is very high.
However, in the electrode-built-in susceptor 1, an oxidization resistance in the power supplying terminal 6 is not sufficient; therefore, there is a problem in that a durability to a thermal cyclic load decreases under condition in an oxidizing atmosphere at a temperature higher than 400° C.
For such a case, it is proposed that a periphery of the power supplying terminal is cooled. When the periphery of the power supplying terminal 6 is cooled, there are other problems in that the plate sample takes more time to be heated at a predetermined temperature and that a uniform thermal disposition in the plate sample decreases.